Use of tetrahydropyridines in the treatment of sodium channel related disease and disorders

ABSTRACT

The present invention provides a method of treating one or more sodium channel related diseases or disorders in an individual, including related symptoms. The method comprises administering to the individual a tetrahydropyridine derivative in an amount effective to treat sodium channel related diseases or disorders in individuals. These compounds are generally categorised as Ritalin related compounds. The present invention also provides compounds for use in the treatment of and also for use in the manufacture of a medicament for the treatment of sodium channel related diseases or disorders in an individual. A method is further provided for the preparation and isolation of the derivatives of the compound of the present invention.

FIELD OF INVENTION

The present invention relates generally to sodium channel relateddiseases and disorders, including but not limited to hyperactivityrelated, muscular, bladder, immune system and neurological disorders.

BACKGROUND OF INVENTION

The following discussion of the background of the invention is intendedto facilitate an understanding of the present invention. However, itshould be appreciated that the discussion is not an acknowledgement oradmission that any of the material referred to was published, known orpart of the common general knowledge in any jurisdiction as at thepriority date of the application.

Sodium channels are the founding members of the superfamily of ionchannels that includes voltage gated potassium and calcium channels.Unlike the different classes of potassium and calcium channels, however,functional properties of the known sodium channels (NaV) are relativelysimilar. Voltage gated sodium site 2 channels which are found in centralneurons, are primarily localized to unmyelinated and pre-myelinatedaxons, govern action potential initiation and repetitive firing. Sodiumchannels play an important role in the neuronal network by transmittingelectrical impulses rapidly throughout cells and cell networks, therebycoordinating higher processes including but not limited to locomotion,cognition and pain. These channels are large transmembrane proteins,which are able to switch between different states to enable selectivepermeability for sodium ions. For this process an action potential isneeded to depolarize the membrane, and hence these channels arevoltage-gated.

Voltage-gated sodium channels are classified based on their sensitivityto tetrodotoxin, from low nanomolar (Tetrodotoxin sensitive, TTXs) tohigh micromolar (Tetrodotoxin resistant, TTXr). So far, 9 differentsodium channel a subunits have been identified and classified as Na_(v)1.1 to Na_(v) 1.9. Na_(v) 1.1 to Na_(v) 1.4, Na_(v) 1.6 and Na_(v) 1.7are TTXs, whereas Na_(v) 1.5, Na_(v) 1.8 and Na_(v) 1.9 are TTXr, withdifferent degrees of sensitivity. Na_(v) 1.1 to Na_(v) 1.3 and Na_(v)1.6 are primarily expressed in the central nervous system (CNS), whereasNa_(v) 1.4 and Na_(v) 1.5 are mainly expressed in muscle (skeletal andheart respectively). Na_(v) 1.7, Na_(v) 1.8 and Na_(v) 1.9 arepredominantly expressed in dorsal root ganglion (DRG) sensory neurons.

Several diseases, disorders and their symptoms, are related to abnormalsodium channel conductance. These include hyperactivity related,muscular, bladder, immune system, neurological disorders, pain,convulsion, inflammation and even cancer. Voltage-gated sodium channelsexpressed in non-nervous or non-muscular organs are often associatedwith the metastatic behaviour of different cancers and have beenimplicated in the pathology of different cancers such as prostate,breast, lung (small cells and non-small cells) and leukaemia (Roger S etal., Curr Pharm Des 2006, 12(28):3681-3695; Li M and Xiong Z G, Int JPhysiol Pathophysiol Pharmacol 2011, 3(2):156-166).

Autism spectrum disorder (ASD) is characterized by social deficits andcommunication difficulties, stereotyped or repetitive behaviours andhyperactivity. Through whole exome sequencing, candidate genes with denovo mutations, including SCN1A which codes for Na_(v) 1.1, have beenrecently identified in sporadic ASD (Eijkelkamp et al., Brain, 2012,135, 2585-2612). Although initially thought to be different, it has beenrecently found that autism, attention deficit-hyperactivity disorder(ADHD), bipolar disorder, major depressive disorder and schizophrenia,all share common genetic underpinnings (Soretti A and Fabbri C, Lancet,2013, 381 (9875), 1339-1341). These disorders, their pathophysiology andcurrent treatment are summarized in the fifth revision of the AmericanPsychiatric Association's Diagnostic and Statistical Manual of MentalDisorders 5^(th) edition (DSM-5), published in 2013, and theEncyclopedia of Psychopharmacology (Springer 2010).

Voltage-gated sodium channel channelopathies such as paramyotoniacongenital and periodic paralysis affecting skeletal muscles can befound in SCN4A/Na_(v)1.4. Mutations in Na_(v) 1.4 can result in ionicleak through the gating pore allowing sustained inward sodium flux atnegative membrane potentials. Such mutations can also enhance activationor impair inactivation resulting in hyperexcitability (Eijkelkamp etal., Brain, 2012, 135, 2585-2612).

It is believed that changes in the isoforms of sodium channels causeabnormal ectopic firing of the DRG, causing spontaneous ectopicdischarges. This can lead to an overactive bladder, characterized byurgency, frequency and nocturia, with or without urge incontinence(Steers W D, Rev Urol 2002, 4 (Suppl4), S7-S18).

In multiple sclerosis, demyelination of axons occur in patients, whichlead to ectopic action potential firing that is caused by slowsodium-dependent membrane potential oscillations (Eijkelkamp et al.,Brain, 2012, 135, 2585-2612).

Mutations in the gene encoding Na_(v) 1.1 and Na_(v) 1.2 have shown tobe involved in the pathophysiology of both acquired and inheritedepilepsy, where the active state of sodium channels are favoured,resulting in the potentiation of electrical signal propagation whichleads to maximal seizure activity and its spread (Zuliani V. et al.,Curr Top Med Chem, 2012, 12(9), 962-70).

A number of drugs having an unknown mechanism of action actually act bymodulating sodium channel conductance, including local anesthetics,class I antiarrhythmics and anticonvulsants. Ion channel targeted drugshave always been related with either the CNS, the peripheral nervoussystem, or the cardiovascular system (Waszkielewicz A M et al., Curr MedChem, 2013, 20, 1241-1285). Neuronal sodium channel blockers have foundapplication with their use in the treatment and alleviation of theabovementioned diseases, disorders and symptoms, for example, epilepsy(phenyloin and carbamazepine), bipolar disorder (lamotrigine),preventing neurodegeneration, and in reducing neuropathic pain. Variousantiepileptic drugs that stabilize neuronal excitability are effectivein neuropathic pain (e.g. carbamazepine).

However, there is still a need for improved methods and compounds intreating and alleviating sodium channel related diseases, disorders andsymptoms, for example lowering dosage but maximising drug effects inaddressing these diseases, disorders and symptoms.

Threo- and erythro-diastereomers of methylphenidate are known to bind todopamine and serotonin receptors, where the threo form is commonlyprescribed to patients as a racemate for the treatment of ADHD (DaviesH. M. L. et al., Bioorg Med Chem Lett, 2004, 14, 1799-1802). This isiterated in WO 2007106508 A2 where methylphenidate also interacts withnorepinephrine, serotonin and dopamine transporters, most of them in themicromolar range. However, the present inventors have found thatmethylphenidate and its analogues, strongly bind to sodium channels, inparticular to sodium channel site 2—this is not disclosed nor suggestedin the prior art. Further, the IC₅₀ values for the antagonistic bindingactivity of the compound in WO 2007106508 A2 to serotonin 5-HT2A and5-HT2C receptors are in the micromolar range, which should not besufficient to elucidate the desired pharmacological effects. Moreover,the synthesis of the methylphenidate analogues in WO 2007106508 A2involve a rhodium catalyst which will be an issue in an activepharmaceutical product since the amount of heavy metals is strictlyregulated and is limited to rhodium at 10 ppm for oral dosing and 1 ppmfor parental administration.

Therefore the object of the present invention is to provide for animproved use of methylphenidate analogues for the treatment of sodiumchannel related diseases and disorders. The present invention alsoprovides an improved process of synthesizing methylphenidate analoguesto increase the safety and efficacy of the resultant compounds.

SUMMARY OF INVENTION

The present invention provides a method of treating one or more sodiumchannel related diseases or disorders in an individual, includingrelated symptoms. The method comprises administering to the individual atetrahydropyridine derivative in an amount effective to treat sodiumchannel related diseases or disorders in individuals. These compoundsare generally categorised as Ritalin related compounds.

The present invention also provides compounds for use in the treatmentof and also for use in the manufacture of a medicament for the treatmentof sodium channel related diseases or disorders in an individual.

A method is further provided for the preparation and isolation of thederivatives of the compound of the present invention. Preferably, thethreo- and erythro-diastereomers, and threo- and erythro-enantiomers arepurified and isolated.

Sodium channel related diseases or disorders include but are not limitedto hyperactivity related disorders (e.g. attention deficit hyperactivitydisorder (ADHD), autism spectrum disorder (ASD) andschizophrenia-related hyperactivity), muscular disorders (e.g.bronchospasm and oesophageal spasm), bladder disorders (e.g. urinaryincontinence and irritable bowel syndrome (IBS)), immune systemdisorders (e.g. multiple sclerosis), neurological disorders (e.g.schizophrenia, epilepsy and migraine) and cancer. Symptoms related to atleast one of the above diseases or disorders include but are not limitedto pain, convulsion and inflammation.

In particular embodiments, the compositions administered according tothe method of the invention comprises a compound having the followinggeneral structure (1):

its diastereomer, enantiomer, racemic mixture, salts or a combinationthereof, wherein R is selected from a group comprising hydrogen, alkyl,alkenyl, alkoxy, halo, nitro, cyano, keto, amino, carboxylate,substituted or unsubstituted phenyls, adjacent rings which share a sidewith the R-bearing group, or a combination thereof. The R-bearing groupis preferably mono-, di-, or tri-substituted.

Preferably, the compound is a threo-diasteromer, erythro-diastereomer ora mixture of the threo-diastereomer and the erythro-diastereomer. It ispreferable that the compound has one of the following structures (2and/or 3):

Preferably, the compound operates by inhibiting sodium channelconductance, where the sodium channels are voltage gated sodiumchannels. It is also preferred that the compound operates by binding tosite 2 of voltage gated sodium channels.

Further, it is preferred that the compound also binds to serotoninreceptors, particularly but not limited to serotonin 5-HT_(2A)receptors.

BRIEF DESCRIPTION OF FIGURES/DRAWINGS

The present invention will now be described, by way of example only,with reference to the accompanying drawing, in which:

FIG. 1 provides a HPLC trace of EXAMPLE 1 on an ECLIPSE XDB-C18, 5 μm,4.6×150 mm column, flow 1 ml/min. Solvent phase A: 0.05% TFA in water,solvent phase B: 0.05% TFA in acetonitrile. Gradient (time/% B): 0/5 5/515/90 20/90 20.1/5 25/5.

FIG. 2 provides a HPLC trace of EXAMPLE 1 on a Diacel chiralpak IA3, 3μ,4.6×250 mm column, flow 1 ml/min. Solvent: 0.1% DEA in hexane:IPA(99:1%), isocratic.

FIG. 3 provides an analytical HPLC trace of Enantiomer M and EnantiomerN separation on a Diacel CHIRALPAK IA3, 3μ, 4.6×250 mm column, flow 1ml/min. Solvent: 0.1% DEA in hexane: Ethanol (99:1%), isocratic.

FIG. 4 provides an analytical HPLC trace of EXAMPLE 1E separation on aDiacel CHIRALPAK IA3, 3μ, 4.6×250 mm column, flow 1 ml/min. Solvent:0.1% DEA in hexane: Ethanol (99:1%), isocratic. Both enantiomers arepresent in equal amounts.

FIG. 5 provides a table showing the results of the binding of thedisclosed EXAMPLEs to sodium channel site 2 and serotonin 5-HT_(2A)binding sites expressed in % binding at the maximal concentration testedas well as IC50, Ki and nH for concentration-response curves.

FIG. 6 provides a graph showing the percentage inhibition of [3H]Batrachotoxinin against log concentration (μm) of EXAMPLE 1.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a method of treating one or more sodiumchannel related diseases or disorders in an individual, includingrelated symptoms. The method comprises administering to the individual atetrahydropyridine derivative in an amount effective to treat sodiumchannel related diseases or disorders in individuals.

The term “individual” used in the specification herein describes ananimal, preferably a human.

It is contemplated that a constellation of sodium channel relateddiseases, disorders and symptoms in the same individual, can be treatedor alleviated by the present invention. In this regard, recognisingsodium channel related diseases, disorders and symptoms and thetreatment and/or alleviation of the same, during or after practice ofthe present invention is well within the purview of a person havingordinary skill in the art and can be performed using any suitableclinical, diagnostic, observational or other techniques. Treatment of adisease or disorder is understood to include anything done or providedfor alleviating or preventing the effects or symptoms of the disease ordisorder, whether it is done or provided by way of cure or not. Areduction in any particular symptoms—including symptoms that are not aresult of sodium channel related diseases or disorders, but aregenerally related to abnormal sodium channel conductance—resulting frompractising the present invention, is considered an alleviation of thesymptom.

Sodium channel related diseases or disorders generally involve abnormalsodium channels conductance and overexpressed sodium channels. Abnormalconductance across sodium channels can result from abnormal channelaperture and/or frequency of the opening/closing of the sodium channeldue to mutations in sodium channel proteins or binding of smallmolecules to sodium channel protein sites. Such abnormal conductanceinclude but are not limited to persistent sodium currents resulting fromsodium channels generating much longer openings as a result ofincomplete or defective fact inactivation and resurgent sodium currentswhich may arise following relief of ultra-fast open-channel block. It isalso contemplated that overexpression of sodium channels may increaseexcitability of the cells (e.g. neurons) in which they are located.Accordingly, sodium channel related diseases or disorders include butare not limited to hyperactivity related disorders (e.g. attentiondeficit hyperactivity disorder (ADHD) and autism spectrum disorder(ASD)), muscular disorders (e.g. bronchospasm and oesophageal spasm),bladder disorders (e.g. urinary incontinence and irritable bowelsyndrome (IBS)), immune system disorders (e.g. multiple sclerosis),neurological disorders (e.g. schizophrenia, epilepsy and migraine) andcancer. Symptoms related to at least one of the above diseases ordisorders are well-known and include but are not limited to pain,convulsion and inflammation. Recognising and determining a reduction inthe symptoms of any of these diseases or disorders can be readilyperformed by those skilled in the art.

Sodium channels described herein include but are not limited to sodiumchannels which channel openings are triggered by voltage change (e.g.voltage gated, voltage sensitive and voltage dependent sodium channels)or ligand binding (e.g. ligand gated sodium channels).

The compounds of the present invention can be understood to modulatesodium channel conductance by binding to sodium channels, for thepurposes of treating sodium channel related diseases or disorders, wheresuch modulation includes but is not limited to complete or partialinhibition, or reduction in sodium channel conductance.

Compositions comprising an effective amount of the compound may beadministered via any conventional route. Such routes include but are notlimited to orally, parenterally, intramuscularly, intravenously,mucosally and transdermally.

Determining a dosage regime of the compounds is well within the purviewof those skilled in the art. By way of example, doses between 0.1 mg and1,000 mg are considered. It will be recognised by that dosingparameters, in addition to the weight of the individual, also take intoaccount the age of the individual and the stage of the disease orseverity of the disorder, and can be determined according toconventional procedures.

Other components may be combined with the compounds to formpharmaceutical preparations for use in the present method. Suchcomponents can be selected depending on factors which include but arenot limited to the dosage form, particular needs of the patient, andmethod of manufacture, among other things. Examples of such componentsinclude but are not limited to binders, lubricants, fillers, flavorings,preservatives, colorings, diluents, etc.

Additional information regarding pharmaceutical composition componentsfor use with the present method are described in Remington'sPharmaceutical Sciences (18^(th) Edition, A. R. Gennaro et al. Eds.,Mack Publishing Co., Easton, Pa., 1990). Accordingly, the selection ofparticular substances and their compatibilities with the compositions ofthe present invention can be readily ascertained by those of ordinaryskill in the art.

The compound and its diastereomers, enantiomers, racemic mixtures, salts(including but not limited to pharmaceutically acceptable salts, chiralsalts and such chiral salts crystallized, e.g. lactic or tartaric acid),or any combination thereof, can function as sodium channel inhibitors,which have surprisingly shown to have significant therapeutic utility inhumans. Said compound can also include any chiral stationary phaseemployed for the resolution of their enantiomers. For example,Lamotrigine, generally accepted to be a member of the sodium channelblocking class of antiepileptic drugs, has been shown to be a safe andeffective treatment option for adult ADHD comorbid with bipolar andrecurrent depression (Öncü et al., J Psychopharmacol, 2014, 28(3),282-283). Furthermore, the compound and its derivatives of the presentinvention has been found to bind to serotonin receptors, in particular5-HT_(2A) receptors, acting as antagonists which are known asantipsychotic agents and which can improve cognitive function inpatients. The compound and its derivatives have been found to inhibitand/or reduce the activity of serotonin receptors. This suggests thatthere is a combined activity of the compound and its derivatives on bothsodium channel receptors and serotonin receptors, where such combinationwill be beneficial as the cognitive function will be improved andhyperactivity will be reduced. The dual functionality and mechanism canbe applied specifically for the use in treatment-resistant settings.

The compounds in the present invention, including its diastereomers,enantiomers, racemic mixtures, diastereomeric mixtures and saltsthereof, having the following general structure (1), have shown toexhibit favourable biological activity in in vitro pharmacologicalreceptor studies:

R is selected from a group comprising hydrogen, halo, substituted orunsubstituted phenyls, adjacent rings which share a side with theR-bearing group, or a combination thereof. It would be understood that Rcan also be selected from a group comprising alkyl, alkenyl, alkoxy,nitro, cyano, keto, amino and carboxylate. The R-bearing group ispreferably mono-, di-, or tri-substituted. Preferably R represents oneor more substituents selected from the group consisting of hydrogen,halogens, substituted or unsubstituted phenyls, and adjacent rings whichshare a side with the R-bearing group. Preferred are substituents suchas hydrogen, unsubstituted phenyls, one or more chlorines, bromine, andsingle adjacent aromatic rings which, together with the R-bearing ring,comprise a naphthyl group. Accordingly, the term “derivative” refers toa compound or compounds which have the general structure (1) or arederived from compounds having the general structure (1) through achemical or physical process, and includes but is not limited todiastereomers, enantiomers and salts.

R-groups in the para-position of the R-bearing ring, such as anunsubstituted phenyl in the para-position on the R-bearing ring;chlorine substituents at either or both the meta and/or para positions,a bromine substituent at the para-position; and one adjacent ring suchthat, together with the R-bearing ring, it comprises a para-2-naphthylgroup, are preferred. It is preferably that the compound has thestructure (2) and/or structure (3):

The synthesis of the compound having the general structure (1), itsthreo- and erythro-diastereomers and enantiomers are described herein.The synthesis reaction includes the use of a non-chiral rhodium catalyst(rhodium (II) octanoate dimer). The choice of the catalyst comes with asignificant reduction in costs and allows the access of a new syntheticroute which moves the use of the rhodium catalyst to an earlier step inthe synthetic route. While a rhodium catalyst is used in said synthesisreaction, said reaction avoids rhodium catalyst in the last reactionsteps, which is useful since the compounds described herein are intendedgenerally for pharmaceutical applications, whereby the amount of heavymetals is heavily regulated and is limited for Rhodium at 10 ppm fororal dosing and 1 ppm for parenteral administration. Accordingly, therhodium catalyst and any rhodium derivatives are substantially removedfrom the mixture containing the compound of the present invention,including its threo- and erythro-diastereomers and enantiomers, wherethe term “substantially” means that the amount of rhodium remaining inthe mixture, is equal to or less than 10 ppm for oral dosing, or 1 ppmfor parental administration. Suitable purification and isolationtechniques to obtain the final chemical products (i.e. the threo- anderythro-diastereomers and enantiomers) of the reaction can be readilydetermined according to conventional procedures, for example by means ofcolumn chromatography, chiral high-performance liquid chromatography(HPLC) and crystallisation. For the avoidance of doubt, a protectinggroup used herein refers to a chemical group which is capable ofreacting with a functional group in a compound, for the purposes ofprotecting the functional group from a reaction. Protecting groupsinclude but are not limited to tert-Butyloxycarbonyl (BOC),carbobenzyloxy (Cbz), p-Methoxybenzyl carbonyl (Moz) and acetyl (Ac)groups.

While the invention is illustrated by way of the following examples, theexamples are meant only to illustrate particular embodiments of thepresent invention and are not meant to be limiting in any way.

PREPARATION EXAMPLES

This representation provides representative procedures for making thecompound having the structure (2), its threo- and erythro-diastereomers,and enantiomers. The steps of this example would be understood by aperson having ordinary skill in the art to also apply to the synthesisof other tetrahydropyridine derivatives with the general formula (1),where the utilization of different reactants and implementation ofdifferent experimental conditions would be routine for a skilled personin order to optimise the synthesis of the desired compounds.

Preparation of Example 1

The general synthesis of the compound having structure (2) is summarizedand exemplified for EXAMPLE 1. Synthesis of EXAMPLE 1 was achieved infive steps, starting from the commercially available2-[(1,1′-biphenyl)-4-yl] acetic acid Compound A. Compound A wasesterified followed by treatment with tosyl azide to afford IntermediateC, which was treated with D in presence of Rh (II) octanoate to affordIntermediate E as an inseparable mixture of diastereomers. IntermediateE was subjected to Boc-removal with TFA to afford Intermediate F, whichupon treated with HCl-MTBE to afford EXAMPLE 1 (Scheme 1).

1. Preparation of methyl biphenyl-4-ylacetate, Intermediate B

A solution of biphenyl-4-ylacetic acid (10.0 g, 47.1 mmol) in MeOH (100mL) was charged with sulfuric acid (10 mL) at 0° C. The reaction mixturewas stirred to reflux for 16 h. The reaction mixture was concentratedunder the reduced pressure, diluted with ice water (100 mL) and wasextracted with MTBE (2×100 mL). The combined organic layers were washedwith saturated NaHCO₃ solution (100 mL), water (100 mL) and brine (50mL). The organic layers were dried over anhydrous Na₂SO₄ and wereconcentrated under reduced pressure to afford methylbiphenyl-4-ylacetate (Intermediate B, 9.80 g, 92%) as a colourlessliquid.

¹H NMR (CDCl₃): δ 7.49-7.44 (m, 4H), 7.35-7.23 (m, 5H), 3.60 (s, 3H),3.56 (s, 2H).

2. Preparation of Methyl [2-(biphenyl-4-yl)-diazoacetate, Intermediate C

A solution of methyl biphenyl-4-ylacetate (Intermediate B, 9.80 g, 43.3mmol) in acetonitrile (50 mL) was charged with DBU (9.80 g, 65.0 mmol)followed by a solution of tosylazide (10.2 g, 52.0 mmol) in acetonitrile(48 mL) dropwise at 0° C. over 10 min. The reaction mixture was stirredat room temperature for 16 h. The reaction mixture was concentratedunder reduced pressure, diluted with 5% KOH solution (200 mL) and wasextracted with MTBE (3×200 mL). The combined organic layers were washedwith water (100 mL) and brine (50 mL). The organic layers were driedover anhydrous Na₂SO₄ and were concentrated under reduced pressure toafford methyl [2-(biphenyl-4-yl)-diazoacetate (Intermediate C, 9.00 g,82%) as a yellow solid.

¹H NMR (CDCl₃): δ 7.64-7.53 (m, 6H), 7.46-7.31 (m, 3H), 3.88 (s, 3H).

3. Preparation of tert-butyl6-(2-methoxy-2-oxo-1-phenylethyl)-3,6-dihydropyridine-1(2H)-carboxylate,Intermediate E

A solution of Rhodium (II) octanoate dimer (0.30 g, 0.39 mmol) in1,2-dimethylbutane (200 mL) was charged with a solution of tertbutyl 5,6dihydropyridine-1(2H)-carboxylate (Intermediate D, 11.1 g, 63.4 mmol) in1,2-dimethylbutane (100 mL) at room temperature.[2-(biphenyl-4-yl)-diazoacetate (Intermediate C, 4.00 g, 15.8 mmol) in1,2-dimethylbutane and toluene (300 mL, 2:1) were added to the reactionmixture dropwise over 15 min at room temperature. The reaction mixturewas stirred at room temperature for 1 h. The reaction mixture wasconcentrated under reduced pressure and the residue was purified bycolumn chromatography to afford tertbutyl6-(2-methoxy-2-oxo-1-phenylethyl)-3,6-dihydropyridine-1(2H)-carboxylate(Intermediate E, 3.00 g, 46%) as an off-white solid.

¹H NMR (CDCl₃): δ 7.52-7.42 (m, 4H), 7.39-7.24 (m, 5H), 5.86-5.74 (m,2H), 4.20-4.15 (m, 1H), 3.74 (d, J=10.4 Hz, 1H), 3.64 (s, 3H), 2.88-2.81(m, 1H), 2.27-2.15 (m, 1H), 1.98-1.77 (m, 1H), 1.46-1.39 (m, 1H), 1.09(s, 9H).

4. Preparation of methylbiphenyl-4-yl(1,2,5,6-tetrahydropyridin-2-yl)acetate, Intermediate F

A solution of tert-butyl6-(2-methoxy-2-oxo-1-phenylethyl)-3,6-dihydropyridine-1(2H)-carboxylate(Intermediate E, 3.00 g, 7.37 mmol) in CH₂Cl₂ (30 mL) was charged withTFA (5.7 mL, 74 mmol) dropwise at 0° C. over 5 min. The reaction mixturewas stirred at room temperature for 2 h. The reaction mixture wasconcentrated under reduced pressure and was cooled to 0° C. The reactionmixture was basified to pH 10 with saturated NaHCO₃ solution (25 mL),extracted with CH₂Cl₂ (3×20 mL), washed with water (10 mL) and brine (10mL). The combined organic extracts were dried over anhydrous Na₂SO₄ andwere concentrated under the reduced pressure. The residue was purifiedby column chromatography to afford methylbiphenyl-4-yl(1,2,5,6-tetrahydropyridin-2-yl)acetate (Intermediate F,2.00 g, 88%) as an off-white solid.

¹H NMR (CDCl₃): δ 7.59-7.55 (m, 4H), 7.49-7.32 (m, 5H), 5.91-5.69 (m,2H), 5.30-5.27 (m, 1H), 4.04-3.99 (m, 1H), 3.70-3.69 (d, J=3.6 Hz, 3H),3.65-3.57 (m, 1H), 3.09-2.76 (m, 2H), 2.22-2.05 (m, 1H), 2.04-1.98 (m,1H).

5. Preparation of EXAMPLE 1, methylbiphenyl-4-yl(1,2,5,6-tetrahydropyridin-2-yl)acetate hydrochloride salt

A solution of 6 (2.00 g, 6.5 mmol) in MTBE (20 mL) was charged with HClin diethyl ether (1.0 M, 32 mL, 32 mmol) over 2 min at 0° C. Thereaction mixture was stirred at room temperature for 2 h. The resultedsolid was collected by filtration, washed with pentane (100 mL) and wasdried under vacuum to afford EXAMPLE 1 (methylbiphenyl-4-yl(1,2,5,6-tetrahydropyridin-2-yl)acetate hydrochloride salt,1.50 g, 67%, 98.7% AUC by HPLC) as an off-white solid. The twodiastereomers in EXAMPLE 1 elute from an ECLIPSE XDB-C18 column withretention times of 12.4 min and 12.6 min, respectively (FIG. 1), in aratio of 2.16:1. On a chiral Diacel column, all 4 enantiomers can beanalytically separated with retention times of 14.5 min, 18.0 min, 19.5min and 21.5 min, respectively (FIG. 2).

¹H NMR (DMSO-d6): δ 9.73 (d, J=6.0 Hz, 1H), 9.39 (s, 0.3H), 8.62 (s,0.7H), 7.75-7.39 (m, 9H), 6.07-5.90 (m, 1H), 5.69 (d, J=10.8 Hz, 0.7H),5.19 (d, J=10.2 Hz, 0.3H), 4.49-4.52 (m, 1H), 4.15-4.30 (m, 1H), 3.67(d, J=3.3 Hz, 3H), 3.50 (s, 1H), 3.22-3.03 (m, 2H), 2.22 (t, J=13.5 Hz,1H).

Preparation of the Example 1 Enantiomers: Example 1A, Example 1B,Example 1C and Example 1D

Synthesis of EXAMPLE 1A, EXAMPLE 1B, EXAMPLE 1C and EXAMPLE 1D werefollowed up to the synthesis of the diastereomers of Intermediate F fromthe commercially available 2-[(1,1′-biphenyl)-4-yl]acetic acid themethod as described above. Biphenyl-4-yl acetic acid was esterifiedfollowed by treatment with tosyl azide to afford Intermediate C, whichwas treated with Intermediate D in presence of Rh(II) octanoate toafford Intermediate E as an inseparable mixture of diastereomers.Intermediate E was subjected to Boc-removal followed by purification bysilica chromatography to afford the Diastereomers of Intermediate F,erythro-Diastereomer G and threo-Diastereomer H (Scheme 2).

Diastereomer G was subjected to chiral-prep-HPLC to afford Enantiomers Iand K, which upon treated with HCl to afford EXAMPLE 1A and EXAMPLE 1B(Scheme 3). Absolute stereochemistry of EXAMPLE 1A and EXAMPLE 1B werenot assigned.

Diastereomer H was treated with Boc-anhydride to afford Intermediate L,which was subjected to chiral-prep-HPLC purification to affordEnantiomers M and N. Enantiomers M and N on removal of Boc with TFAafforded Enantiomers O and P, which were treated with HCl to affordEXAMPLE 1C and EXAMPLE 1 D, respectively (Scheme 4).

1. Preparation of Erythro-Enantiomers I, K and Threo-Diastereomer H

A solution of Intermediate E (2.80 g, 6.80 mmol) in CH₂Cl₂ (28 mL) wascharged with TFA (5.29 mL, 68.0 mmol) dropwise at 0° C. over 5 min. Thereaction mixture was stirred at room temperature for 2 h. The reactionmixture was concentrated under reduced pressure and was cooled to 0° C.The reaction mixture was basified to pH≈10 with saturated NaHCO₃solution (25 mL), extracted with CH₂Cl₂ (3×20 mL), washed with water (10mL) and brine (10 mL). The reaction mixture was dried over anhydrousNa₂SO₄ and was concentrated under reduced pressure. The residue waspurified by column chromatography to afford Erythro-Diastomer G (0.60 g)and Threo-Diastereomer H (0.90 g, 42%) as off-white solids.Erythro-Diastereomer G (0.60 g) was purified by chiral prep HPLC (0.1%of DEA in hexane:IPA, 99:1, Daicel CHIRALPAK IA, 250 mm×20 mm, 5μ, 12mL/min; 0.60 g of mixture was dissolved in 30 mL of mobile phase and 4.0mL was injected every 30 min) to afford Enantiomer I (0.20 g, 9.5%) as afirst eluting enantiomer (22 min) followed by Enantiomer K (0.20 g,9.5%) as a second eluting enantiomer (26 min) as off-white solids.

Enantiomers I and K:

¹H NMR (400 MHz, CDCl₃): δ 7.51-7.47 (m, 4H), 7.37-7.31 (m, 4H),7.28-7.24 (m, 1H), 5.73-5.68 (m, 1H), 5.23-5.20 (m, 1H), 3.97-3.93 (m,1H), 3.61 (s, 3H), 3.51 (d, J=10.4 Hz, 1H), 3.04-2.99 (m, 1H), 2.88-2.82(m, 1H), 2.15-2.05 (m, 1H), 1.92-1.85 (m, 2H).

Threo-Diastereomer H:

¹H NMR (400 MHz, CDCl₃): δ 7.58-7.56 (m, 4H), 7.48-7.41 (m, 4H),7.36-7.32 (m, 1H), 5.91-5.87 (m, 1H), 5.73-5.69 (m, 1H), 4.02-3.98 (m,1H), 3.69 (s, 3H), 3.62 (d, J=10.4 Hz, 1H), 3.00-2.95 (m, 1H), 2.82-2.76(m, 1H), 2.21-2.12 (m, 1H), 2.04-2.02 (m, 1H).

2. Preparation of Biphenyl-4-yl[1,2,5,6-tetrahydropyridin-2-yl]acetatehydrochloride, Example 1A

A solution of Enantiomer I (0.18 g, 0.58 mmol) in MTBE (13.5 mL) wascharged with HCl in diethyl ether (1.0 M, 2.93 mL, 2.93 mmol) over 2 minat room temperature. The reaction mixture was stirred at roomtemperature for 1 h. The reaction mixture was concentrated under thereduced pressure. The residue was triturated with pentane (20 mL),filtered and was dried under vacuum to afford(S,S)-biphenyl-4-yl[-1,2,5,6-tetrahydropyridin-2-yl]acetatehydrochloride (EXAMPLE 1A, 0.17 g, 85%, >99% AUC by HPLC, >99.0% (ee),m/z 308 [M+H]+) as a light yellow solid.

¹H NMR (400 MHz, DMSO-d6): δ 9.63 (bs, 1H), 9.27 (bs, 1H), 7.72-7.67 (m,4H), 7.49-7.36 (m, 5H), 5.92 (d, J=10.0 Hz, 1H), 5.19 (d, J=10.0 Hz,1H), 4.57 (bs, 1H), 4.22 (d, J=9.6 Hz, 1H), 3.68 (s, 3H), 3.35-3.17 (m,2H), 2.27 (bs, 2H); mp=187° C.-189° C.; [α]25 D −173.2° (c 0.05, CHCl₃).

3. Preparation of Biphenyl-4-yl[1,2,5,6-tetrahydropyridin-2-yl]acetatehydrochloride, Example 1B

Using a similar procedure to that described for the preparation ofEXAMPLE 1A, compound Enantiomer K (0.20 g, 0.65 mmol) afforded(R,R)-biphenyl-4-yl[-1,2,5,6-tetrahydropyridin-2-yl]acetatehydrochloride (EXAMPLE 1B, 0.19 g, 85%, 97.6% AUC by HPLC, 98.6% (ee),m/z 308 [M+H]+) as a light yellow solid.

¹H NMR (400 MHz, DMSO-d6): δ 9.63 (bs, 1H), 9.27 (bs, 1H), 7.72-7.67 (m,4H), 7.49-7.36 (m, 5H), 5.92 (d, J=10.0 Hz, 1H), 5.19 (d, J=10.0 Hz,1H), 4.57 (bs, 1H), 4.22 (d, J=9.6 Hz, 1H), 3.68 (s, 3H), 3.35-3.17 (m,2H), 2.27 (bs, 2H); mp=187° C.-189° C.; [α]25 D+184.8° (c 0.05, CHCl₃).

4. Preparation of Enantiomers M and N

A solution of Diastereomer H (0.90 g, 6.80 mmol) in CH₂Cl₂ (40 mL) wascharged with TEA (0.79 mL, 5.82 mmol) followed by a solution of (Boc)₂O(0.73 mL, 3.22 mmol) in CH₂Cl₂ (10 mL) dropwise over 5 min at 0° C. Thereaction mixture was stirred at room temperature for 2 h. When TLCanalysis showed consumption of starting material, the reaction mixturewas diluted with water (50 mL) and was extracted with CH₂Cl₂ (2×30 mL).The combined organic layers were washed with brine (20 mL). The layerswere dried over anhydrous Na₂SO₄ and were concentrated under the reducedpressure. The residue was purified by column chromatography to afford amixture of enantiomers M and N (0.90 g), which was purified by chiralprep HPLC (0.1% of DEA in hexane:EtOH, 99:1%, Daicel CHIRALPAK IA, 250mm×20 mm, 5μ, 10 mL/min, 1.0 mL loop, 0.90 g of enantiomeric mixture(FIG. 3) was dissolved in 80 mL of mobile phase and for every 10 minaliquots were injected) to afford Enantiomer N (0.20 g, 16.8%) as firsteluting enantiomer (6 min) followed by Enantiomer M (0.20 g, 16.8%) assecond eluting enantiomer (7 min) as off-white solids.

Enantiomers M and N:

¹H NMR (300 MHz, CDCl₃): δ 7.52-7.42 (m, 4H), 7.36-7.25 (m, 5H),5.84-5.73 (m, 2H), 4.20-4.14 (m, 1H), 3.73 (d, J=10.2 Hz, 1H), 3.64 (s,3H), 2.89-2.80 (m, 1H), 2.25-2.13 (m, 1H), 1.93-1.88 (m, 1H), 1.46-1.42(m, 1H), 1.09 (s, 9H).

5. Preparation of Enantiomer O

A solution of Enantiomer M (0.20 g, 0.49 mmol) in CH₂Cl₂ (2.0 mL) wascharged with TFA (0.37 mL, 4.9 mmol) dropwise at 0° C. over 1 min. Thereaction mixture was stirred at room temperature for 2 h. The reactionmixture was concentrated under reduced pressure and was cooled to 0° C.The reaction mixture was basified to pH 10 with saturated NaHCO₃solution (5.0 mL), extracted with CH₂Cl₂ (3×5.0 mL), washed with water(5.0 mL) and brine (5.0 mL). The reaction mixture was dried overanhydrous Na₂SO₄ and was concentrated under reduced pressure. Theresidue was purified by column chromatography to afford Enantiomer O(0.10 g, 66%) as an off-white solid.

¹H NMR (400 MHz, CDCl₃): δ 7.58-7.56 (m, 4H), 7.48-7.41 (m, 4H),7.36-7.32 (m, 1H), 5.91-5.86 (m, 1H), 5.73-5.70 (m, 1H), 4.02-3.98 (m,1H), 3.69 (s, 3H), 3.62 (d, J=10.4 Hz, 1H), 3.01-2.95 (m, 1H), 2.82-2.76(m, 1H), 2.21-2.12 (m, 1H), 2.04-1.98 (m, 1H).

6. Preparation of Methyl(2R)-biphenyl-4-yl[(2S)-1,2,5,6-tetrahydropyridin-2-yl]acetatehydrochloride, Example 1C

Using a similar procedure to that described for the preparation ofEXAMPLE 1A, Enantiomer O (0.10 g, 0.32 mmol) afforded Methyl(2R)-biphenyl-4-yl[(2S)-1,2,5,6-tetrahydropyridin-2-yl]acetatehydrochloride, EXAMPLE 1C (0.11 g, 99%, 96.5% AUC by HPLC, 94.4% (ee),m/z 308 [M+H]+) as a light yellow solid.

¹H NMR (400 MHz, DMSO-d6): δ 9.55 (bs, 1H), 8.59 (bs, 1H), 7.74-7.68 (m,4H), 7.58-7.37 (m, 5H), 6.05 (d, J=8.0 Hz, 1H), 5.69 (d, J=9.6 Hz, 1H),4.50 (bs, 1H), 4.15 (d, J=10.4 Hz, 1H), 3.67 (s, 3H), 3.20-3.03 (m, 2H),2.50 (bs, 1H), 2.22-2.18 (m, 1H); mp=194° C.-196° C.; [α]25 D+106.4° (c0.05, CHCl₃).

7. Preparation of Enantiomer P

Using a similar procedure to that described for the preparation ofEnantiomer O, compound Enantiomer N (0.20 g, 0.49 mmol) affordedEnantiomer P (0.10 g, 66%) as a light yellow solid.

¹H NMR (400 MHz, CDCl₃): δ 7.58-7.56 (m, 4H), 7.48-7.41 (m, 4H),7.36-7.32 (m, 1H), 5.91-5.86 (m, 1H), 5.73-5.70 (m, 1H), 4.02-3.98 (m,1H), 3.69 (s, 3H), 3.62 (d, J=10.4 Hz, 1H), 3.01-2.95 (m, 1H), 2.82-2.76(m, 1H), 2.21-2.12 (m, 1H), 2.04-1.98 (m, 1H).

8. Preparation of Methyl(2S)-biphenyl-4-yl[(2R)-1,2,5,6-tetrahydropyridin-2-yl]acetatehydrochloride, Example 1D

Using a similar procedure to that described for the preparation ofEXAMPLE 1C, Enantiomer P (0.10 g, 0.32 mmol) afforded Methyl(2S)-biphenyl-4-yl[(2R)-1,2,5,6-tetrahydropyridin-2-yl]acetatehydrochloride, EXAMPLE 1D (0.11 g, 99%, 96.1% AUC by HPLC, 98.2% (ee),m/z 308 [M+H]+) as a light yellow solid.

¹H NMR (400 MHz, DMSO-d6): δ 9.55 (bs, 1H), 8.59 (bs, 1H), 7.74-7.68 (m,4H), 7.58-7.37 (m, 5H), 6.05 (d, J=8.0 Hz, 1H), 5.69 (d, J=9.6 Hz, 1H),4.50 (bs, 1H), 4.15 (d, J=10.4 Hz, 1H), 3.67 (s, 3H), 3.20-3.03 (m, 2H),2.50 (bs, 1H), 2.22-2.18 (m, 1H); mp=184° C.-186° C.; [α]25 D −98.0° (c0.05, CHCl₃).

Scalable Procedure to Obtain Methyl(2R)-biphenyl-4-yl[(2S)-1,2,5,6-tetrahydropyridin-2-yl]acetatehydrochloride, Example 1C, and Methyl(2S)-Biphenyl-4-Yl[(2R)-1,2,5,6-tetrahydropyridin-2-yl]acetatehydrochloride, Example 1 D, as Enantiomeric Mixture

In order to obtain a scalable procedure to obtain Methyl(2R)-biphenyl-4-yl[(2S)-1,2,5,6-tetrahydropyridin-2-yl]acetatehydrochloride, EXAMPLE 1C, and Methyl(2S)-biphenyl-4-yl[(2R)-1,2,5,6-tetrahydropyridin-2-yl]acetatehydrochloride, EXAMPLE 1 D, as enantiomeric mixture starting fromIntermediate C, the synthetic steps were optimized as follows:

1. Scalable preparation of tert-butyl6-(2-methoxy-2-oxo-1-phenylethyl)-3,6-dihydropyridine-1(2H)-carboxylate,Intermediate E

A solution of Rhodium (II) octanoate dimer (1.00 g, 1.38 mmol) inn-hexane (50 mL) was charged to a solution of tertbutyl 5,6dihdropyridine-1(2H)-carboxylate (Intermediate D, 10.1 g, 55.4 mmol) inn-hexane (100 mL) at room temperature. A solution of 3 (14.0 g, 55.4mmol) in toluene (40 mL) was added to the above reaction mixturedropwise over 15 min. The reaction mixture was stirred at roomtemperature for 1 h. The reaction mixture was filtered through celitebed, washed with n-hexane (100 mL) and the filtrate was concentratedunder reduced pressure to afford tert-butyl6-(2-methoxy-2-oxo-1-phenylethyl)-3,6-dihydropyridine-1(2H)-carboxylate,Intermediate E, (24.0 g, crude) as a blue oil.

Analytical HPLC analysis of the crude product by Eclipse XDB-C18 columnindicated the presence of the two diastereomers in 49% and 20%,respectively.

2. Scalable preparation of methylbiphenyl-4-yl(1,2,5,6-tetrahydropyridin-2-yl)acetate, Intermediate F

A solution6-(2-methoxy-2-oxo-1-phenylethyl)-3,6-dihydropyridine-1(2H)-carboxylate(24.0 g, crude) in CH₂Cl₂ (150 mL) was charged with TFA (48 mL, 2 vol)dropwise at 0° C. over 15 min. The reaction mixture was stirred at roomtemperature for 2 h. The reaction mixture was concentrated under reducedpressure. The reaction mixture was diluted with CH₂Cl₂ (150 mL) and pHof the solution was adjusted to 10 with saturated NaHCO₃ solution (250mL). The layers were separated and the aqueous layer was extracted withCH₂Cl₂ (3×200 mL). The combined organic layers were washed with water(200 mL) and brine (100 mL). The organic layers were dried overanhydrous Na₂SO₄ and concentrated under the reduced pressure to affordmethyl biphenyl-4-yl(1,2,5,6-tetrahydropyridin-2-yl)acetate,Intermediate F (16.5 g, crude) as a brown oil.

Analytical HPLC analysis of the crude product by Eclipse XDB-C18 columnindicated the presence of the two diastereomers in 41% and 22%,respectively.

3. Scalable Preparation of Example 1, methylbiphenyl-4-yl(1,2,5,6-tetrahydropyridin-2-yl)acetate hydrochloride salt

A solution methyl biphenyl-4-yl(1,2,5,6-tetrahydropyridin-2-yl)acetate(16.5 g, crude) in 1,4-dioxane (100 mL) was charged with HCl in1,4-dioxane (4 M, 33 mL, 2 vol) over 10 min at 0° C. The reactionmixture was stirred at room temperature for 2 h. The reaction mixturewas concentrated under reduced pressure, washed with MTBE (50 mL) andwas dried under vacuum to afford methylbiphenyl-4-yl(1,2,5,6-tetrahydropyridin-2-yl)acetate hydrochloride salt(EXAMPLE 1, 13.5 g, crude) as a light brown solid.

Analytical HPLC analysis of the crude product by Eclipse XDB-C18 columnindicated the presence of the two diastereomers in 50% and 23%,respectively.

4. Scalable preparation of Example 1E (Enantiomeric pair consisting ofMethyl (2R)-biphenyl-4-yl[(2S)-1,2,5,6-tetrahydropyridin-2-yl]acetatehydrochloride, Example 1C, and Methyl(2S)-biphenyl-4-yl[(2R)-1,2,5,6-tetrahydropyridin-2-yl]acetatehydrochloride, Example 1D)

A solution of methylbiphenyl-4-yl(1,2,5,6-tetrahydropyridin-2-yl)acetate hydrochloride salt(10.0 g, crude) in acetonitrile (40 mL) was charged with Methyltert.-butyl ether (80 mL) and water (7.0 mL) at room temperature. Thereaction mixture was stirred for 10 min at room temperature. Theresulted solids were filtered, washed with Methyl tert.-butyl ether (25mL) and was dried to afford EXAMPLE 1E (Enantiomeric pair consisting ofMethyl (2R)-biphenyl-4-yl[(2S)-1,2,5,6-tetrahydropyridin-2-yl]acetatehydrochloride, EXAMPLE 1C, & Methyl(2S)-biphenyl-4-yl[(2R)-1,2,5,6-tetrahydropyridin-2-yl]acetatehydrochloride, EXAMPLE 1 D, 3.75 g) as a light brown solid (96.8% HPLCpurity, m/z 308 [M+H]+). The compound was found to be soluble in DMSOand acetonitrile/water. Chiral chromatography (FIG. 4) revealed thepresence of both enantiomers in equal amounts.

Working Examples

This representation demonstrates the receptor binding properties of thecompounds of the present invention. For this representation, theactivities of EXAMPLE 1, EXAMPLE 1A, EXAMPLE 1B, EXAMPLE 1C, EXAMPLE 1D,and EXAMPLE 1E versus sodium channel site 2 and serotonin 5-HT2A bindingsites were determined in radioligand binding studies. Functional studieson serotonin-induced IP1 increase in CHO cells were performed todetermine agonist or antagonist activity.

Radioligand Binding Data

Sodium Channel Site 2 Binding:

The method employed in this study has been adapted from Catterall W A,Morrow C S, Daly J W and Brown C B (J Biol Chem. 256(17):8922-8927,1981). Dibucain was used as reference standard as an integral part ofeach assay to ensure the validity of the results obtained:

Materials:

[3H] Batrachotoxinin were prepared and purified as described. [3H]Batrachotoxinin is stable in storage for up to 1 year and is stable at37° C. for the duration of these experiments.

Experimental:

Whole brains (except cerebellum) of male Wistar derived rats weighing175 +/−25 g are used to prepare sodium channel site 2 in modifiedHEPES/Tris-HCl buffer: 130 mM choline chloride, 50 mM4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) 50 mM Trisadjusted to pH 7.4 at 37° C. 130 mM Choline Chloride, 5.4 mM KCl, 0.8 mMMgCl₂, 5.5 mM Glucose, 40 μg/ml scorpion venom from Leiurusquinquestriatus (LqTx). A 7.5 mg membrane aliquot is incubated with 5 nM[3H]Batrachotoxinin for 60 minutes at 37° C. Non-specific binding isestimated in the presence of 100 μM veratridine. Membranes are filteredand washed, the filters are then counted to determine[3H]Batrachotoxinin specifically bound. Compounds, dissolved in DMSO,are screened at a concentration range between 1 nM and 10 μM. Inprevious studies, the maximal binding capacity of [3H]Batrachotoxinin(Bmax) and its Kd were determined and amount to 0.70 pmol/mg Protein and52 nM, respectively.

Serotonin 5-HT2A Binding:

Human recombinant serotonin 5-HT_(2A) receptors expressed in CHO-K1cells are used in modified Tris-HCl buffer pH 7.4. A 30 μg aliquot isincubated with 0.5 nM [3H]Ketanserin for 60 minutes at 25° C.Nonspecific binding is estimated in the presence of 1 μMMianserin.Receptors are filtered and washed, the filters are thencounted to determine [3H]Ketanserin specifically bound. Compounds,dissolved in DMSO, are screened at a concentration range between 3 nMand 30 μM. In previous studies, the maximal binding capacity of[3H]Ketanserin (Bmax) and its Kd were determined and amount to 510fmol/mg protein and 0.2 nM, respectively.

Data Evaluation:

IC₅₀ values and Hill coefficient (nH) were determined by a non-linear,least squares regression analysis using MathIQ™ (ID Business SolutionsLtd., UK). The Ki values were calculated using the equation of Cheng andPrusoff (Biochem. Pharmacol. 22:3099-3108, 1973) using the observed IC₅₀of the tested compound, the concentration of radioligand employed in theassay, and the historical values for the KD of the ligand (as determinedpreviously).

Results:

The binding data for the examples of the current embodiment aresummarized in FIG. 5.

Serotonin-Mediated Inositol Phosphate Response

The 5-HT₂ receptor class couples preferentially to Gq/G11 to increasehydrolysis of inositol phosphates and elevate cytosolic [Ca²⁺]. Humanrecombinant serotonin 5-HT_(2A) receptor stably expressed in CHO-K1cells are used. Test compound and/or vehicle is incubated with the cells(5×105/ml) in stimulation buffer of IP1 Tb kit (Cisbio Bioassays) for 30minutes at 37° C. Test compound-induced increase of fluorescencerelative to the 10 μM serotonin response indicate possible serotonin5-HT_(2A) receptor agonist activity. Test compound-induced inhibition of0.3 μM serotonin-induced fluorescence response indicated receptorantagonist activity. EXAMPLE 1, EXAMPLE 1C and EXAMPLE 1D are screenedat 1 μM demonstrated no agonist activity but antagonism of inhibition of0.3 μM serotonin-induced fluorescence response by 30% and 37%,respectively.

Electrophysiology

Effects on Human Na_(v) 1.1, Na_(v) 1.2, Nav1.3, Na_(v) 1.4, Na_(v) 1.5,Na_(v) 1.6, Na_(v) 1.7 and Na_(v) 1.8/β3 Sodium Channels Expressed inMammalian Cells

CHO cells were stably transfected with human ion channel cDNAs. Stabletransfectants were selected by expression with the antibiotic-resistancegene(s) incorporated into the expression plasmid(s). Selection pressurewas maintained by including selection antibiotics in the culture medium.CHO cells were cultured in Ham's F-12 supplemented with 10% fetal bovineserum, 100 U/mL penicillin G sodium, 100 μg/mL streptomycin sulfate andappropriate selection antibiotics. Before testing, cells in culturedishes were washed twice with Hank's Balanced Salt Solution (HB-PS) andtreated with Accutase for approximately 20 minutes. Immediately beforeuse in IonWorks Barracuda™, the cells were washed in HB-PS to remove theAccutase and re-suspended in HB-PS. All experiments were performed atambient temperature. Test articles and reference compound (lidocaine)concentrations were applied to naïve cells (n=4, where n=the number ofreplicate wells/concentration) via 384-channel pipettor. Duration ofexposure to each test article concentration was five (5) minutes.Inhibition of Na_(v) channels was measured using a stimulus voltagepattern. The pulse pattern was repeated before (baseline) and for five(5) minutes after compound addition. Peak current amplitudes weremeasured for test pulses TP1 (inactivated state inhibition), TP2, TP3(tonic inhibition) and TP22 (use-dependent inhibition).

Concentration-response data were fit to an equation of the followingform:

% Block=(100%)/[1+([C]/IC50)^(N)],

where [C] was the concentration of test article, IC50 was theconcentration of the test article producing half-maximal inhibition, Nwas the Hill coefficient, % VC was the percentage of the currentrun-down (the mean current inhibition at the vehicle control) and %Block was the percentage of ion channel current inhibited at eachconcentration of a test article. Nonlinear least squares fits weresolved with the XLfit add-in for Excel (Microsoft, Redmond, Wash.). IC50values of block for each Na_(v) 1.x channel with the test article arepresented in the Table below:

EXAMPLE 1C EXAMPLE 1D EXAMPLE 1E Lidocaine IC₅₀, μM IC₅₀, μM IC₅₀, μMIC₅₀, μM TP2 TP2 TP2 TP2 TP1 (inactivated TP1 (inactivated TP1(inactivated TP1 (inactivated Channels (tonic) state) (tonic) state)(tonic) state) (tonic) state) 1 Na_(v)1.1 >30 2.1 >30 2.2 >30 1.5 543.2464.9 2 Na_(v)1.2 >30 3.1 >30 2.1 >30 1.5 496.4 410.9 3 Na_(v)1.3 >302.2 >30 2.0 >30 1.3 554.7 164.6 4 Na_(v)1.4 >30 1.5 >30 1.3 >30 1.2389.2 162.1 5 Na_(v)1.5 >30 1.5 >30 2.0 >30 1.2 381.1 27.0 6Na_(v)1.6 >30 2.2 >30 2.0 >30 1.2 422.7 187.6 7 Na_(v)1.7 >30 2.5 >302.0 >30 1.3 381.6 153.5 8 Na_(v)1.8 >30 1.9 >30 1.8 >30 1.1 279.8 51.4

Both EXAMPLE 1C, EXAMPLE 1D, and EXAMPLE 1E showed inhibition to Na_(v)1.1 to Na_(v) 1.8 and were more than 10 to 100 times more potent thanLidocaine in blocking the inactivated state of the channels.

Those skilled in the art will appreciate that the invention describedherein is susceptible to variations and modifications other than thosespecifically described. The present invention includes all suchvariations and modifications. The invention also includes all of thesteps, features, formulations and compounds referred to or indicated inthe specification, individually or collectively and any and allcombinations or any two or more of the steps or features.

Each document, reference, patent application or patent cited in thistext is expressly incorporated herein in their entirety by reference,which means that it should be read and considered by the reader as partof this text. That the document, reference, patent application or patentcited in this text is not repeated in this text is merely for reasonsfor conciseness.

Any manufacturer's instructions, descriptions, product specifications,and product sheets for any products mentioned herein or in any documentincorporated by reference herein, are hereby incorporated herein byreference, and may be employed in the practice of the invention.

The present invention is not to be limited in scope by any of thespecific embodiments described herein. These embodiments are intendedfor the purposes of exemplification only. Functionally equivalentproducts, formulations and methods are clearly within the scope of theinvention as described herein.

The invention described herein may include one or more ranges of values(e.g. concentration). A range of values will be understood to includeall values within the range, including the values defining the range,and values adjacent to the range which lead to the same or substantiallythe same outcome as the values immediately adjacent to that value whichdefines the boundary to the range.

Throughout the specification, unless the context requires otherwise, theword “comprise” or variations such as “comprises” or “comprising”, willbe understood to imply the inclusion of a stated integer or group ofintegers but not the exclusion of other integer or group of integers. Itis also noted that in this disclosure and particularly in the claimsand/or paragraphs, terms such as “comprises”, “comprised”, “comprising”and the like can have the meaning attributed to it in U.S. Patent law;e.g., they can mean “includes”, “included”, “including”, and the like;and that terms such as “consisting essentially of” and “consistsessentially of” have the meaning ascribed to them in U.S. Patent law,e.g., they allow for elements not explicitly recited, but excludeelements that are found in the prior art or that affect a basic or novelcharacteristic of the invention.

Other definitions for selected terms used herein may be found within thedetailed description of the invention and apply throughout. Unlessotherwise defined, all other scientific and technical terms used hereinhave the same meaning as commonly understood to one of ordinary skill inthe art to which the invention belongs.

While the invention has been described with references to specificmethods and embodiments, it will be appreciated that variousmodifications and changes may be made without departing from theinvention.

REFERENCES

-   1. Soretti A and Fabbri C, 2013. “Shared genetics among major    psychiatric disorders.” Lancet 381 (9875): 1339-1341.-   2. Waszkielewicz A M, Gunia A, Szkaradek N, Słoczyńska K S, S.    Krupinska S, Marona A (2013). “Ion channels as drug targets in    central nervous system disorders.” Curr Med Chem 20, 1241-1285.-   3. Roger S, Potier M, Vandier C, Besson P and Le Guennec J Y (2006).    “Voltage-gated sodium channels: new targets in cancer therapy?” Curr    Pharm Des 12(28): 3681-3695-   4. Li M and Xiong Z G (2011). “Ion channels as targets for cancer    therapy.” Int J Physiol Pathophysiol Pharmacol 2011, 3(2):156-166-   5. Eijkelkamp N, Linley J E, Baker D M, Minett M S, Cregg R,    Werdehausen R, Rugiero F and Wood J N (2012). “Neurological    perspectives on voltage-gated Sodium channels.” Brain 135:    2585-2612.-   6. Steers W D (2002). “Pathophysiology of overactive bladder and    urge urinary incontinence.” Rev Urol 4 (Suppl4):S7-S18.-   7. Zuliani V, Fantini M, Rivara M (2012). “Sodium channel blockers    as therapeutic target for treating epilepsy: recent updates.” Curr    Top Med Chem 12(9):962-70.-   8. Davies H. M. L. et al. (2004). “Synthesis of methylphenidate    analogues and their binding affinities at dopamine and serotonin    transport sites.” Bioorg Med Chem Lett, 2004, 14, 1799-1802.

1. A method of treating one or more sodium channel related diseases ordisorders in an individual, comprising administering to the individual acomposition comprising a compound in an amount effective to treat thediseases or disorders, wherein the compound has the following structure(1):

its diastereomer, enantiomer, racemic mixture, salts or a combinationthereof, wherein R is selected from a group comprising hydrogen, alkyl,alkenyl, alkoxy, halo, nitro, cyano, keto, amino, carboxylate,substituted or unsubstituted phenyls, adjacent rings which share a sidewith the R-bearing group, or a combination thereof.
 2. The methodaccording to claim 1, wherein the R-bearing group is mono-, di-, ortri-substituted.
 3. The method according to claim 1, wherein thecompound is a threo-diastereomer, a erythro-diastereomer or a mixture ofthe threo-diastereomer and the erythro-diastereomer.
 4. The methodaccording to claim 1, wherein R is one or more substituents selectedfrom the group consisting of hydrogen, halogens, substituted orunsubstituted phenyls, and adjacent rings which share a side with theR-bearing group.
 5. The method according to claim 1, wherein R consistsof chlorine substituents at positions 3 and
 4. 6. The method accordingto claim 1, wherein R is a p-bromo.
 7. The method according to claim 1,wherein R is a p-chloro.
 8. The method according to claim 1, wherein Ris a p-2-naphthyl.
 9. The method according to claim 1, wherein R is anunsubstituted p-phenyl.
 10. The method according to claim 6, wherein thecompound has the following structure (2):


11. The method according to claim 6, wherein the compound has thefollowing structure (3):


12. The method according to claim 6, wherein the compound comprisesmixture of structures (2) and (3).
 13. The method according to claim 1,wherein the compound is capable of inhibiting sodium channelconductance.
 14. The method according to claim 13, wherein the sodiumchannels are voltage gated sodium channels.
 15. The method according toclaim 1, wherein the compound is capable of inhibiting serotoninreceptors and reducing the activity of serotonin receptors.
 16. Themethod according to claim 1, wherein the compound is administeredorally, parenterally, intramuscularly, intravenously, mucosally ortransdermally.
 17. The method according to claim 1, wherein the one ormore sodium channel related diseases or disorders is selected from thegroup consisting of hyperactivity related, muscular, bladder, immunesystem or neurological disorders.
 18. The method according to claim 17,wherein the one or more sodium channel related diseases or disorders isselected from the group consisting of autism spectrum disorder (ASD),attention deficit hyperactivity disorder (ADHD), schizophrenia-relatedhyperactivity, bronchospasm, oesophageal spasm, irritable bowel syndrome(IBS), urinary incontinence, schizophrenia, epilepsy, migraine, andmultiple sclerosis. 19-22. (canceled)
 23. The method according to claim1, wherein the one or more sodium channel related diseases or disordersis cancer.
 24. The method according to claim 1, wherein the methodfurther includes alleviating one or more symptoms of the one or moresodium channel related diseases or disorders, wherein the symptomsinclude pain, convulsion and inflammation. 25-80. (canceled)